The present invention relates to an organometal complex and a chemical vapor deposition (CVD) or atomic layer deposition (ALD) method for preparing a metal silicate thin layer using same.
As semiconductor devices become more highly integrated, electrostatic capacitance becomes smaller in proportion to the size reduction of memory devices. Although the electrostatic capacitance can be increased by reducing the thickness of a gate insulating layer, a silicon oxide gate layer previously used in the art gives problems associated with increases in the channel electric field, interface trap concentration, and leakage current.
To solve such problems, several attempts have been made to develop a dielectric material for a gate insulating layer having higher dielectric constant than silicon dioxide, low leakage current and low interface density. In particular, silicate has been considered to be a promising candidate for a new dielectric material having high performance characteristics.
There have been reported several methods for depositing a metal silicate insulating layer by atomic layer chemical vapor deposition (ALCVD) (M. Ritala, K. et al., Science 299:319, 2000; Roy G. Gorden, et al., Chem. Mater. 13:2463, 2001). However, these methods require the use of two precursors, a metal precursor and a silicon precursor, which have similar decomposition characteristics. Further, the thin layer prepared by such methods often contain an unacceptable certain level of impurities.
The present inventors have therefore endeavored to develop an improved method for depositing a metal silicate gate insulating layer by ALD using a precursor containing both silicon and metal.
Accordingly, an object of the present invention is to provide an organometal complex and a chemical vapor deposition or atomic layer deposition method for preparing a metal silicate thin layer using same.
In accordance with one aspect of the present invention, there is provided a method for atomic layer deposition(ALD) of a metal silicate thin layer which comprises contacting the vapor of an organometal complex of Formula 1 with a substrate:
(X)a-b-M-(Y-(Si(R)3)m)bxe2x80x83xe2x80x83 less than Formula 1 greater than 
wherein M is a trivalent metal ion such as Al, La and Bi, or a tetravalent metal ion such as Zr and Hf;
R is C1-4 alkyl;
X is halogen or C1-4 alkyl;
Y is O or N;
a is 3 and b is an integer ranging from 1 to 3 when M is a trivalent metal ion, or a is 4 and b is an integer ranging from 1 to 4 when M is a tetravalent metal ion; and
m is 1 when Y is O, or m is 2 when Y is N.
In accordance with another aspect of the present invention, there is provided an organometal complex of Formula 2 and a preparing method thereof.
(X)a-b-M-(Nxe2x80x94(Si(R)3)2)bxe2x80x83xe2x80x83 less than Formula 2 greater than 
wherein M, R, X, a and b are the same as defined above.